Work Step by Step
In the second root, we see that $x$ is raised to an even power, so it will always be positive. Thus, for the value inside root to be positive, it follows that y must be positive. This is required since it is an even root. In the first root, since $y$ must be positive, $x$ also must be positive to end up with a positive expression inside the root. This is also required, for the root is even.